Vapor-arc rectifier.



F. CONRAD.

VAPOR ARC RECTIFIER.

APPLICATION FILED mun, 19x4.

Patented Apr. 30, 1918.

I INVENTOR ATTORNEY )QygNESSFS:

UNITED STATES" PATENT OFFICE.

FRANK CONRAD, or SWISSVALE, PENNSYLVANIA, AssIeNoR T0 WESTINGHOUSE ELEC-' TRIO AND MANUFACTURING COMPANY, A CoRPoRA'rIoN or PENNSYLVANIA.

VAPOR-ARC RECTIFIER.

Specification of Letters Patent.

Patented Apr. 30, 1918.

Application filed-May 11, 1914. Serial No. 837,720.

To all whom it may concern:

' Be it known that I, FRANK zen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new be quickly and easily constructed and assembled, that will thoroughly insulate the conducting member from the wall of the containing receptacle, and that will maintain an air tight joint throughout a wide range of temperature changes.

In the accompanying drawing, Figure 1 is. a view of my improved seal, partiall in elevation and partially in section; an Fig. 2 is a fragmentary view, in section, of a modified form of the insulating bushing employed.

Referring to Fig. 1, 3 is the flat cover of the containing receptacle of'avapor arc rectifier, and is preferably a steel for 'ng. opening, preferably circular in out ine, is cut in the cover 3 for the reception of an insulat-' ing bushing 4 carrying any desired conducting member, such, for example, as an anode stem 5. The insulating bushing 4 is pro vided with an exterior flange 18 having an upper plane surface 9 and a lower plane surface 19. The surface 19 is seated on the upper surface of a flange 6 on the cover. In order that the insulating bushing 4 may be accurately centered in the opening in the cover, the latter is provided with an inwardly extending member 11 adapted to bear against the lower portion of the bushing. A peripheral flange 6 surrounds the opening in the cover and is exteriorly threaded to engage with an interiorly threaded collar 7 An exteriorly threaded ring 8 engages the collar 7 and bears upon the flat shoulder 9 of the insulating bushing 4, allowance being made for expansion and CONRAD, a citicontraction by a compressible gasket 10 of some refractory fibrous material, such, ,for example, as asbestos.

The bushing 4 is also provided with an interior flange 12 having plane upper and lower beafing surfaces 13 and 13 anode stem 5 is provided with a shoulder 17 having a plane upper surface 13 adapted to bear against the lower face of the flange 12. The anode stem 5 is threaded, as shown at 14, and an interiorly threaded sleeve 15 engages therewith and bears upon the upper surface of the flange 12, through a compres-f sible gasket 16 of asbestos or similar material. The anode stem 5 is accurately centered in the bushing 4 by engagement therewith at the point 17 After the seal is assembled, as above described, spaces 20, 21, 22, 23, 24, 25 and 31 may be filled with any suitable sealing liquid, such, for example, as mercury, and, if the device is to be mounted upon a moving vehicle, such as a railway locomotive, the sealing liquid may bev retained in place by wax or other suitable means.

The flange 18 is forced to withstand the pressure of the clamping device provided between bushing 4 and cover 3 and the flange 12 is obliged to withstand the pressure of the clamping device between the bushing 4 and anode stem 5-.- Very heavy strains are accordingly exerted upon the comparatively small section of vitreous material connecting these two flanges, frequently causin fracture at this point. I have obviated t is'difficulty by makin the interior and the exterior flanges of t e insulating bushing 4 of considerable thickness, as shown at 26 and 27 in Fig. 2. These flanges are so placed as to overlap to a marked degree,thus providing a large cross section of the vitreous material at the point of maximum strain. Flanges 26 and 27 are under-cut,- as shown at 28, in order that the strain shall be uniformly distributed upon the bearing surfaces 29 and 30.

I am aware that it is old to clamp an anode stem into the cover of a metallic containing receptacle, as shown for example in United States patent to Sakai No. 1,049,404; but, in all seals of thistharacter that have The ' surfaces between the bushing and the cover and between the stem and the bushing have been conical in shape. llt is extremely dificult, under such conditions, to obtain an accurate fit between thetwo bearing surfaces,

I since a different mechanism must be employed to machine each type of surface, and

all such mechanism must be set at a definite adjusted angle. My improved seal has plane bearing surfaces throughout, a plane surface being the easiest type to machine with accuracy. Seals of the Sakai type must be ground together, as is the ordinary practice with the valves of automobile engines, and while, by this means, a close fit may-be obtained in each particular case, yet the elements of such seals are not interchangeable. In my seal, the bearing sur faces being perfectly plane, absolute interchangeabillty is inherent.

In the manufacture of a forged steel cover, such as 3, it is extremely diflicult to entirely free the metal from internal stress. The result of this is that, when the cover is heated in the operation of the rectifier, it expands much morealong a certain diameter than it does in other directions. This unequal ex pansion causes what was previously a circular seat to become slightly elliptical and hence causes an unavoidable leak in a conical seal but has no effect whatsoever upon my seal.

The tendency of the clamping elements in a seal of the Sakai type is to burst the insulating bushing. Vitreous material, such as porcelain, is ill. adapted to withstand a bursting strain, owing to its low tensile strength. I eliminate all bursting strains and use the material of the insulating bushing entirely in compression.

While I have described the anode stem, the insulating bushing, and the opening in the cover of the containing receptacle all as being circular in shape, it will be understood that they may be made elliptical, square, or

of any other desired shape I shall accordnaeaate andsurrounding the insulating bushing, an

exteriorly threaded ring engaging the collar and bearing upon the exterior flange of the bushing, a conducting member provided with. a peripheral flange projecting through the bushing, said peripheral flange engaging the interior flange of the bushing in a plane bearing surface, and means for clamping bearing.

2. The combination with a plate of conducting material provided with an opening therethrough and having an annular groove surrounding said opening, of an insulating bushing provided with a peripheral flange on'its exterior surface, said bushing being seated in said opening and having one face of said flange engaging said plate, a collar surrounding said bushing and in threaded engagement with a wall of said groove, a clamping member surrounding said bushing the conducting member to the insulating" in threaded engagement with said collar and bearing upon the opposite face of said flange,

whereby said bushing is clamped to said plate, and a conducting member extending through said bushing.

In testimony whereof, lihave hereunto subscribed my name this 27th day of April,

FRANK CONRAD. Witnesses v y W. L. Wnronr, B. B. Hmns. 

